For multiple unit, high-speed packaging of liquid or semi-liquid flowable foods products, specialized packaging machinery is used which usually includes multiple pumping arrangements for placing measured amounts of food product into suitable containers. This type of machinery is typically used for packaging of food products such as yogurt, cottage cheese, ice cream, dessert toppings, and other dairy and non-dairy products which are flowable in nature.
Machinery of this description typically includes an arrangement for sequentially presenting a plurality of containers to be filled, usually in groups of several containers for simultaneous filling. Food product is supplied to the machinery from a common source, with each pumping arrangement of the machinery operating in a cyclical fashion so that the groups of containers presented are sequentially filled with product. The containers are then advanced along the production line for checking the weight of the product in the containers, and for closing and labeling the containers for subsequent storage and shipment.
Because economical production demands that each container is filled with the desired quantity of product quickly and accurately, the product pump arrangements of the packaging machinery must be capable of delivering equal amounts of food product to each container each operating cycle. Naturally, stringent sanitary conditions must be maintained throughout all steps of the product packaging operation.
One factor which can considerably complicate accurate and efficient filling of containers with food product relates to the relative compressibility of the product. While some food products are incompressible in nature, many flowable food products are compressible because the product includes air so that the product has the desired texture and consistency. Such food products are sometimes referred to as having "high overrun," and are typified by products such as ice cream, dessert toppings, and the like. Because such products are compressible in nature, filling each container with the desired quantity of product by weight is complicated, since surges in the supply of food product to the packaging machinery, changes in speed of the production line, and like fluctuations in the packaging operation can result in undesired compressing of the food product during packaging, resulting in inaccurate filling of the containers. The positive displacement type pumping arrangements used in packaging machinery for flowable food product have been found to be difficult to adjust for repeated, accurate product packaging of compressible food product in light of the inevitable fluctuations which occur in the packaging operation.
Thus, the introduction of an improved food product fill pump apparatus which is adapted for use with flowable food product which is compressible in nature, and which includes an arrangement for compensating for fluctuations which occur in the packaging operation, is particularly desirable for facilitating economical and high speed multiple unit packaging of the product.